3501. When a magnet is in motion relative to a coil the induced e.m.f. does not depend upon
(a) pole strength of the magnet
(b) motion of the magnet
(c) number of turns of the coil
(d) resistance of the coil
Answer: (d) resistance of the coil

3502. The weight of copper of both armature and field windings decreases with _____ in
number of poles.
(a) decrease
(b) increase
(c) either of the above
(d) none of the above

Answer: (b) increase

3503. Which of the following is the unit of magnetic flux density ?
(a) tesla
(b) lumens
(c) weber
(d) none of the above

Answer: (a) tesla

3504.  Substances which have permeability less than the permeability of free space are known
(a) ferromagnetic
(b) paramagnetic

(c) bipolar
(d) diamagnetic

Answer: (d) diamagnetic

3505. Which of the following methods may be adopted to reduce the effects of armature
reaction ?
(a) Increase in length of air gap at pole tips
(b) Compensating windings
(c) Increasing reluctance of pole tips
(d) Interpoles
(e) All of the above

Answer: (e) All of the above

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